Needle syringe assemblies are well known and have been continually improved upon through the years. The connection between the needle hub and the barrel of the syringe has received considerable attention in that the connection has to be positive, leak proof, quickly made and relatively simple to complete. The well known luer lock on the distal end of the barrel has resulted which includes a male tapered member and an internally threaded luer lock collar. An early form of needle assembly for use with the barrel of a syringe had a needle and a hub, which hub had a segmented radially extending flange or pair of ears on the proximal end thereof. A sheath was provided which fitted over the needle and frictionally engaged the hub. To connect a needle to the barrel, the sheath was manipulated to align the needle hub with the luer lock collar with the segmented flanges on the hub engaging the threads in the collar. The sheath and needle were rotated to thread the hub onto the barrel and to wedge the tapered luer member in the passage in the hub. The sheath then had to be removed. Frequently the fit between the needle hub and the sheath was so tight that damage was done to the connection or to the needle in trying to remove the sheath. Sometimes the fit between the needle hub and the sheath was too loose so that it was almost impossible to get the grip necessary to properly seat the hub on the tapered luer member. To overcome these problems, ribs were put on the hub and coacting keyways were provided in the sheath so that turning the sheath positively turned the needle hub on the threads in the collar and seated the hub on the tapered luer member. The problem of releasing the sheath from the hub still remained.